There are also an additional 5,000 domains with the hydrogen keyword in different variations. Which tells me that keyword usage is high.
Notes:Hydrogen.green at first glance can be seen as water.green (however the actual chemical combination for H2O requires oxygen which can be misleading to it's main purpose. It will not garner the value that H2O.green has -- but can be marketed towards an end-user in the green market.
Keep in mind that .green has not seen very many sales as of recent -- so you must be vigilant in your outbound marketing and promoting of your domain to make a successful sale.
Make sure to consult research with numbers at www.NameBio.com
That is a pretty incredibly awesome and detailed appraisal @M. Harper did!
I just wanted to add one further thought re use. The hydrogen economy, which started with things like fuel cell technology for vehicles but is now much more diverse, is the obvious end user to me.
HD are selling HydrogenGreen in .com I see, not for as much as I might have thought. It does mean that a business by buying that plus yours would have both the exact new extension term and corresponding com, possibly of interest to some end users.